Device for corrugation of strips

ABSTRACT

Device for corrugating strips, comprising punches linked by a driving camshaft, wherein each punch has means for withdrawing it from a cooperating forming surface at the moment of feed of the strip being corrugated. This means includes an auxiliary cam secured on the driving camshaft and a pusher interacting with said auxiliary cam, and secured on one arm of a lever whose other arm is connected to the punch, said lever being adapted for transmitting reciprocating motions to said punch from said camshaft.

United States Patentv Antonenko et al.

1451 Sept. 17, 1974 DEVICE FOR CORRUGATION OF STRIPS [76] lnventors:Grigory Semenovich Antonenko,

ulitsa Yanvarskogo vosstania, Odessa; Avetik Artashesovich Badamian,ulitsa Goncharova, l7, kv. 51, Moscow; Grigory Borisovich Margulis,ploschad Potemkintsev, 3, kv. 2, Odessa; llya Alexandrovich Moroz,ulitsa Varnenskaya, 9, kv. 26, Odessa; Mikhail Borisovich Shitsman,ulitsa Chicherina, 31, kv. 13, Odessa, all of U.S.S.R.

[22] Filed: May 10, 1972 211 App]. No.2 252,034

52 us. c1. 72/385 [51] Int. Cl 821d 13/02 [58] Field of Search 72/385,380, 386, 389, 72/412, 474

[56] References Cited UNITED STATES PATENTS 2,489,125 11/1949 Dyson72/403 3,009,510 1 H1961 Meshulam .7 72/385 3,479,855 11/1969 Ogilvie72/383 FOREIGN PATENTS OR APPLICATIONS 295.121 4/1965 Netherlands 72 3854,215 10/1876 Great Britain 1 72/385 79,227 6/1950 Czechoslovakia 72/385Primary ExarninerCharles W. Lanham Assistant Examiner-Gene P. CrosbyAttorney, Agent, or Firm-Waters, Roditi, Schwartz & Nissen 5 7 ABSTRACTDevice for corrugating strips, comprising punches linked by a drivingcamshaft, wherein each punch has means for withdrawing it from acooperating forming surface at the moment of feed of the strip beingcorrugated. This means includes an auxiliary cam secured on the drivingcamshaft and a pusher interacting with said auxiliary cam, and securedon one arm of a lever whose other arm is connected to the punch, saidlever being adapted for transmitting reciprocating motions to said punchfrom said camshaft.

2 Claims, 3 Drawing Figures PATENIEDSEP 1 71014 SHEET 2 [IF 2 IIIII 1DEVICE FOR CORRUGATION or STRIPS The present invention relates tometal-shaping devices and more particularly it relates to devices forcorrugation of strips.

' The present invention can be used most effectively for making fins offinned-tube heat exchangers which require a high accuracy of thecorrugations with regard to their height,

Known in the art devices for corrugating strips by punches which arekinematically interconnected by a driving camshaft foralternating-opposite reciprocating strokes in a direction perpendicularto a fixed supporting element of one of the punches, said element beingprovided with a slot for the passage of the other punch whose supportingelement is adapted for a joint movement with the first punch in thedirection parallel to the fixed supporting element.

In these known devices the punches are actuated by a single cam whichoperates one of the punches directly, and the other punch via a pusher.In the known devices there is a clearance between each punch and itssupporting element. This clearance is constant and larger than thethickness of the strip being corrugated because this clearance isrequired not only for feeding the strip into the device but also for thefree movement of the movable supporting element with one of the punchesparallel to the fixed supporting element.

The provision of a constant clearance between the punches and theirsupporting elements makes it impossible to produce corrugations of aconstant definite height and of a rectangular shape owing to the freemovement of the strip around the punches.

A constant height of the corrugations becomes particularly important inthe manufacture of the finnedtube heat exchangers. If this requirementis not satisfied, not all corrugations of the strip will be soldered tothe primary surface of the heat exchanger, which will impair its thermalconductivity and strength.

The rectangular shape of the corrugations is vital for better strengthof the corrugated strip in the finnedtube heat exchangers when workingunder medium and high pressures.

It is a well-known fact that the contacting surfaces of the moving partsof any device become gradually worn in operation. This impairs theaccuracy of production, calls for repairs of the devices and leads todifficulties in their operation.

In the known devices the wear of the contacting surfaces of the cam,punch and pusher results in a gradual reduction of the punch stroke. Asa consequence, the clearances between the punches and their supportingelements grow which reduces the height of the strip corrugations.

Besides, wear of the rubbing surfaces of the parts which move one of thepunches parallel to the fixed supporting element reduces this movement.

As a result, the punches start chopping the strip.

An object of the present invention resides in eliminating the aforesaiddisadvantages.

The main object of the invention is to provide a device for corrugatingstrips by punches which are moved in such a manner and have such akinematic linkage with the driving camshaft that the device producescorrugations of an equal height and of a preset shape, and which isconvenient in operation and reliable.

arm of a lever rocking on a fixed rockshaft, the other' arm of thislever being connected with the punch and said lever being adapted fortransmitting reciprocating motions to said punch from said camshaft.

It is advisable that one arm of the lever is made in the form of a yokefitting around the driving camshaft and carrying the pusher of thepunch-withdrawing means on oneend, and a pusher which is in a constantresilient contact with the drive cam of said camshaft on the other.

The device for the corrugation of strips realized according to theinvention produces corrugations of an equal height and of apredetermined shape, is convenient in operation and reliable.

Now the invention will be described in detail by way of example withreference to the accompanying drawings, in which:

FIG. 1 is a longitudinal section, partly cut-away, of the device forcorrugating strips according to the invention;

FIG. 2 is a section taken along line 11-11 in FIG. 1, enlarged; and

FIG. 3a, b, c, d, e, g, i illustrates successive motions of punches inthe process of strip corrugation.

The device for corrugation of strips according to the inventioncomprises punches l and 2 (FIG. I) linked kinematically by a drivingcamshaft to ensure alternating-opposite reciprocating strokes in thedirection of arrow A, perpendicular to a fixed supporting element 3 ofone of the punches 1, 2.

The fixed supporting element 3 is secured on a bed 4 and has a slot 5for the passage of the other punch 2. A supporting element 6 of thepunch 2 is adapted for joint movement with the punch 1 along arrow B,parallel to the fixed supporting element 3.

The supporting element 6 is provided with a slot 6a to allow the passageof the punch 1 therethrough.

According to the invention, each punch has means for withdrawing it fromits supporting element 3 or 6 at the moment of feeding of a strip 7 tobe corrugated.

The punch 1 is withdrawn from its support element 3 by the aid of meanscomprising an additional cam 9 secured on a drive camshaft 8, and apusher 10 coacting therewith, which is mounted on one am C of a lever 11with a stationary rocker shaft 12, while its other arm D is attached tothe punch 1.

The lever 11 is intended for imparting to the punch l reciprocatingmotion from the camshaft 8. In accordance with the invention, the arm Cof the lever 11 is in the form of a yoke embracing the drive camshaft 8and mounting on its one side the pusher 10 of the means to draw off thepunch l, and on its other side a pusher 13 which is in constantresilient contact with a drive cam 14 of the shaft 8.

In the described specific exemplary embodiment of the device, the punchl is secured on a slide 15. Another slide 16) will be described somewhatlater. The slide 15 mounting the punch 1 is disposed in guides 15a ofthe carriage 17 which, in turn, is mounted on rams l8 and is able tomove in guides 18a in the direction of arrow B, parallel to the movablesupport element 3, said guides being provided on the bed 4.

These movements of the carriage 17 in the direction of arrow B, togetherwith the slide 15, are effected by the aid of a cam 19 attached to theshaft 8, as a result of alternating coaction of the cam withspring-loaded pushers that are arranged in diametral relation to the cam19 on a bracket 21 which is attached to the rams 18 by pins 21a.

As shown in FIG. 2, the pusher 13 is a sleeve accommodating a spring 23which thrusts with its one end against the sleeve bottom, while itsother end rests on a bearing 22 (see FIG. 2) which is secured by a screw24. This screw is intended to control the effort of the spring 23, thusproviding a permanent resilient contact between the pusher l3 and thedrive cam 14.

Being similar in design to the pusher 13, pushers 20 are provided with arest shoulder 20a limiting their stroke. Provided inside the pushers 20are springs 23a whose effort is adjusted by screws 20b.

A slide 16 to carry the punch 2 is mounted in guides 16a of the bed 4.

Mounted on a camshaft 8a are cams 9a and 14a which impart reciprocatingmotions to the punch 2 via a pusher 10a and a lever 11a, complete with astationary rocker shaft 12a, which coacts with said earns, thereciprocation being effected in the direction of the arrow A.

Having the same design as the lever 11, the lever 11a comprises an armDa connected to the punch 2, and an arm Ca which is embodied as a yokeembracing the drive camshaft 8a, and mounts on its one side the pusher10a of means to withdraw the punch 2 from its support element 6, whileattached to its other side is a pusher 13a which is in a permanentresilient contact with the drive cam 14a of the camshaft 8a. The designof the pusher 13a is the same as that of the pusher 13. Provided insidethe pusher 13a is a spring 23b whose effort is adjusted by a screw 24b.

In the exemplary embodiment of the device thus described, the camshaftsare operatively interconnected via a gear transmission (not shown in thedrawing), having a gear ratio of 1:1.

These camshafts mount the drive earns 14, 19 and 14a, as well as thecams 9 and 9a of the means to draw off the punches l, 2 at the momentthe strip is being moved, in such a manner as to make the punchesperform, in an alternating order, opposite reciprocating motion, and thepunch 1 performs longitudinal motions.

A few parts not described so far will be explained hereinafter, togetherwith their operation.

The device according to the invention functions as follows. As shown inFIG. 1, on starting an electric motor 25 the camshafts 8, 8a are set inrotation via a V-belt drive 26 and a speed reducer (not shown in thedrawing).

Having been adapted to draw off the punch 1, the additional cam 9 ismounted on the camshaft 8 such that it is able to actuate the punch 1via the pusher 10 and the lever 11, thereby forming a clearance betweenthe punch and its support element 3 at the moment when the punch 2 ispositioned'at its maximum distance from the support element 6. Thisclearance is created owing to a compression of the spring 23 of thepusher 13, which is in permanent resilient contact with the cam 14.

At this very moment the strip 7 to be corrugated is fed along guiderollers 27, which are provided on a bracket 28, into the clearance builtbetween the punch 1 and the support element 3. Then the cam 9,isdisengaged from its contact with the pusher 10, and the punch 1, owingto the effect of the force of the spring 23, which is transmitted by thelever 11, presses the strip 7 against the support element 3 (FIG. 3a).

As the camshafts 8, 8a (FIG. 1) are further rotated, the drive cam 14avia the pusher 13a, which is in permanent resilient contact therewith,and the lever 11a move the punch 2 towards its support element 6. Atthis juncture, the punch 2 presses the strip 7 against the supportelement 6, whereupon the spring 23b of the pusher 13a is compressed,because the cam 14a is able to move the pusher 13a at a distance whichis greater than the total stroke of the punch 2, which is equal to thedistance from the support element 6 to the point at which the punch isfound at the maximum distance from that element (FIG. 30).

As shown in FIG. 1, the drive cam 14 of the shaft 8, while rotating,then enters in contact with the pusher l0 and moves the punch 1, via thelever l 1, drawing the punch off the support element 3 through the fullstroke which is greater than the distance between the elements 3 and 6.

Being adapted to draw off the punch 2, the additional cam via the pusher10a and the lever 11a actuates the punch 2, thereby forming a clearancebetween it and its support element 6 and thus disengaging the strip 7 tobe corrugated (FIG. 36). This clearance is created owing to thecompression of the spring 23b (FIG. 1) of the pusher 13a.

Then the cam 19 coacts with the left-hand pusher 20 and moves thecarriage 17, which is mounted on the rams 18, along the guides 18athrough a full corrugation pitch to the left until an adjusting nut 29thrusts against the bed 4. The full corrugation pitch equals the sum ofthe thicknesses of the punches 1 and 2 and of the double thickness ofthe strip 7 to be corrugated.

Then the spring 23a of the left pusher 20 is compressed, because the cam19 moves the pusher 20 through a distance which is greater than the fullpitch of a corrugation.

The additional cam 9a is disengaged from its contact with the pusher10a, and the punch 2, while being acted upon by the force of the spring23b, which is transmitted by the lever 11a, presses the strip 7 againstthe support element 6 (FIG. 3d).

On having performed all the motions enumerated above, the punches 1 and2 complete the formation of the first half of a corrugation.

As the camshafts 8, 8a are further rotated, the drive cam 14 via thepusher 13, which is in permanent resilient contact therewith, and thelever 11, move the punch 1 towards its support element 3. At thisjuncture, the punch l presses the strip 7 to the support element 3, andthen the spring 23 of the pusher 13 is compressed because the cam isable to move the pusher 13 through a distance which is greater than thefull stroke of the punch 1, which equals the distance from the supportelement 3 to the point wherein the punch is found at its maximumdistance from that element (FIG. 3e).

Then the drive cam 14a (FIG. 1) of the shaft 8a,

while rotating, enters in contact with the pusher 10a and moves thepunch via the lever 11a, drawing the punch of the support element 6through a full stroke which is greater than the distance between theelements 3 and 6.

Being adapted to draw off the punch 1, the additional cam via the pusherl and the lever 11 actuates the punch 1, thereby forming a clearancebetween the punch and its support element 3 and thus disengaging thestrip 7 to be corrugated (FIG. 3g). This clearance is created owing tothe compression of the spring 23 of the pusher 13.

Then the cam 19 (FIG. 1) coacts with the right pusher 20 and moves thecarriage 17 which is mounted on the rams 18in the guides 18a through thefull pitch of a corrugation until an adjusting nut thrusts against thebed 4. At this juncture, the punch 1, while moving together with thecarriage. 17, moves the corrugated strip 7 through one pitch.

Thereafter, the spring 23a of the right-hand pusher 20 is compressedbecause the cam 19 moves the pusher 20 through a stroke which is greaterthan the full pitch of a corrugation.

The additional cam 9 disengages from contact with the pusher l0, and thepunch, while being acted upon by the force of the spring 23, presses thecorrugated strip 7 against the support element 3 (FIG. 3i).

This completes a full revolution of the camshafts 8, 8a, and the punches1, 2, after completing all the movements enumerated above, finish theprocess of manufacturing a complete corrugation. The formation of acomplete corrugation of the strip comes to completion at each subsequentrevolution of the camshafts 8, 8a.

It follows from the above that the strip is corrugated by one of thepunches of the device according to the invention at the moment when thestrip is pressed by the other punch to its supporting, element, whileduring the movement of the strip it is released due to clearances formedbetween the punches and their supporting elements.

Such a design of the device according to the invention makes it possibleto corrugate strips with a particularly high accuracy with regard to theheight of the corrugations.

The height of the corrugations depends on the distance between thesupporting elements. The clearances between the punches and theirsupporting elements ensure the quality and shape of the corrugationsduring the movements of the strip.

It is obvious that the device according to the invention can be used forproducing corrugations of other than rectangular shapes. For thispurpose it is sufficient urations.

The wear of the contacting surfaces of the cams, pushers, and punches inthe device according to the invention exerts no influence on theaccuracy of corrugations relative to their height and on their shapesince the kinematic chain of the device comprises cams which move thepushers through distances larger than required, and resilient elements(springs) which make up for the wear of the contacting surfaces. Thisguarantees a high reliability of the device, renders its convenient inoperation and dispenses with the necessity for frequent adjustments inservice.

The device according to the invention can be used most effectively formaking fins of finned-tube heat exchangers which require particularlyaccurate dimensions of the corrugations with regard to their height.

What we claim is:

1. A device for corrugating a strip, comprising, in combination, a bed,first and second punches operatively interconnected via respective firstand second driving camshaft to perform alternately oppositereciprocating motions in a direction perpendicular to a first stationarysupport element for said first punch, said first element having a slotto allow the passage of said second punch therethrough, the latterhaving a second support element adapted to perform together with saidfirst punch a motion parallel to said first element, said punches beingprovided with means to drawn them off their support elements at themoment of feeding the strip to be corrugated, said drawing meansincluding cams mounted on said camshafts, and pushers coacting with thelatter, said pushers being each secured to one arm of respective levers,having stationary rocker shafts, and being each connected with anotherarm to said punches, and means to reciprocate said punches.

2. The corrugating device as defined in claim 1, wherein said arms ofthe levers are opposite said other arms and are in the form of yokesembracing said camshafts, and mounted on one side are said pushers todraw off said punches, while on their other side there are mountedfurther pushers that are in permanent resilient contact with saidcamshafts.

1. A device for corrugating a strip, comprising, in combination, a bed,first and second punches operatively interconnected via respective firstand second driving camshaft to perform alternately oppositereciprocating motions in a direction perpendicular to a first stationarysupport element for said first punch, said first element having a slotto allow the passage of said second punch therethrough, the latterhaving a second support element adapted to perform together with saidfirst punch a motion parallel to said first element, said punches beingprovided with means to drawn them off their support elements at themoment of feeding the strip to be corrugated, said drawing meansincluding cams mounted on said camshafts, and pushers coacting with thelatter, said pushers being each secured to one arm of respective levers,having stationary rocker shafts, and being each connected with anotherarm to said punches, and means to reciprocate said punches.
 2. Thecorrugating device as defined in claim 1, wherein said arms of thelevers are opposite said other arms and are in the form of yokesembracing said camshafts, and mounted on one side are said pushers todraw off said punches, while on their other side there are mountedfurther pushers that are in permanent resilient contact with saidcamshafts.